The Usambara torrent frog, Martienssen's torrent frog, or Tanzania rocky river frog (Arthroleptides martiensseni) is a species of frog in the Petropedetidae family endemic to the Usambara Mountains of Tanzania. It is one of many, often taxonomically unrelated, frogs referred to as torrent frogs. These frogs are associated with rocky streams in montane forests. Eggs are laid on rocks close to torrential streams and waterfalls. The tadpoles remain attached to the rocks, where they develop, not entering the water. It is threatened by habitat loss.